Sift-proof top closure for bags



Sept. 21, 1954 H. v. KINDSETHQ SIFT-PROOF TOP CLOSURE FOR BAGS Filed Jan. 29, 1951 Enventor 1%"0% fimefi (Ittornega Patented Sept. 21, 1954 UNITED. STATES PATENT OFFICE SIFT-PROOF TOP CLOSURE FOR BAGS Harold V. Kindseth, Minneapolis, Minn., as-v signor to Bemis Bro. Bag (30., Minneapolis, Minn., a corporation of Missouri Application January 29, 1951, Serial No. 208,406

4 Claims. 1

My invention relatesto improvements in top closures for tubular bags and has for its primary object the provision of a sift-proof closure for finely granulated or powdered materials.

Another object of my invention is the novel method of forming a closure of the type abovedescribed, which is inexpensive and easy to form and which results in a closure which is sufficiently strong and durable to withstand rough handling incidental to storage, transportation, stacking, and the like.

The above and still further objects of my invention will become apparent from the followin detailed specification, appended claims, and attached drawings.

Referring to the drawings, wherein like characters indicate like parts throughout the several views: I V,

Fig. 1 is a perspective view of a conventional filled bag with a closure-forming cuff projecting above the fill;

Fig. 2 is a view corresponding to Fig. land illustrating a step in the forming of my novel siftproof closure;

Fig. 3 is a view corresponding to Fig. 2 but illustrating a further step inthe formation of my novel closure; and 1 Fig. 4 is a view corresponding to Fig. 3, showing the final step in the formation of my novel closure.

Referring with greater particularity to the drawings, the numeral I indicates, in its entirety,

a tubular bag having a conventional bottom closure, not shown, formed therein and filled with granular material A, the level of fill being indicated by the numeral 2. Bag I includes end walls 3 and 4 and side walls 5 and 6, the latter of which, along the upper edge 1, is provided with a central notch 8, to permit closures to be formed with the cuff B projecting above the level of fill 2, of the type disclosed and claimed in my copending patent application S. N. 204,394, filed January 4, 1951, and entitled Bag Construction.

The first step in the formation of my novel closure comprises intucking the opposed end walls 3 and 4, as shown in Fig. 2, whereby to provide respectively therewith opposed closure-forming elements 9 and I and upstanding flap-forming elements II and I2 from the opposed side walls and 6 respectively. The opposite end portions of the flap-forming elements I I and I2 are folded over as a result of the intucking of the end walls 3 and 4 to form inner and outer plies I3 and I4,

respectively. Preferably, while the closure-form-' ing elements 8 and I0 and the flap-forming elements II and I2 are in this position, adhesive is.

applied thereto in linear areas I5 and I6, one each of said areas extending completely across the closure-forming elements 9 and I0 in closely spaced parallel relationship to the free edge 1. It will be noted that the opposite ends of the adhesive areas I5 and I6 terminate on the undersurface I? and I8 of the inner plies of the fiapforming elements II and I2, respectively. It will also be noted that the lower. limits I9 of the elongated adhesive areas I5 and I6 are upwardly spaced considerably from the level of fill 2. Preferably and as shown in Fig. 4, adhesive areas I5 and is are sufficiently narrow to be completely covered by the flap-forming elements II and I2 when said flap-forming elements are in the final closure-forming position thereshown.

Also, preferably while the closure-forming elements II and I2 are in the position of Fig. 2, adhesive is applied to a linear area 20 on the undersurface of the outer ply I4 of the: flap-forming element I I. As shown, the upper limits 2| of this adhesive area are adjacent to but spaced below the upper edge 1, whereas the lower limits 22 of said adhesive area 20 are vertically upwardly spaced from the level of fill 2. Laterally, the adhesive area 20 extends substantially across the undersurfaces I1 of the inner plies I3 of the flapforming element II and connects the adjacent ends of the adhesive areas I5 and I6 (see partied? larly Fig. 3). Also, with reference to Fig. 3, it,

will be noted that a substantial quantity of the adhesive applied to the area 20 is introduced on the unclersurface and the inner plies I3 to prevent sifting of the fill therebetween to the exterioroi' the bag. Substantially the areas covered by theadhesive, immediately above described, are defined by dotted lines and indicated at 23. The

size and shape of said areas are of minor importance except that a portion of adhesive must extend fully to the fold lines forming the inner and outer plies of the flap-forming element I I to achieve an effective sift-proof closure when the bag is sealed.

When the adhesive areas I5, I6, and 20 are applied, as above described-and without any regard to the particular manner of applying the adhesive or the particular order in. which said areas are applied-a novel sift-proof top closure may be formed by first folding the flap-forming element I2 over the closure-forming elements 9 and II), as shown in Fig. 3. It will be noted that the substantially parallel adhesive areas I5 and I6, underlying the flap-forming element I2 are caused to be folded backwardly substantially upon themselves, thereby effecting a sift-proof seal at 3 the points indicated by the numerals 24 and 25. Thereafter and lastly, the flap-forming element l! is folded over the closure-forming elements 9 and I8 and the projected end portion 26 of the fiap element 12, whereby to complete the seal. It will be noted, with reference to Fig. 4, that the lower limits 22 of the adhesive 20 are inwardly spaced from the bottom of the notch 8 and hence laterally removed from the contents.

In compliance with Section 4888 of the Revised Statutes, I have disclosed a preferred embodiment of my invention. However, itshould be obvious that the same is capable of modification without departure from the spirit and scope of the invention as defined by the appended claims.

What I claim is: I

1. The method of making a sift-proof top closure from the cuff of a tubular bag projecting above the surface of the fill thereof and wherein said cuff includesend and sidewalls intersecting in vertical lines; said method comprising the following successive steps, folding the end walls inwardly over the fill about horizontal lines adjacent said surface and simultaneously therewith providing fold lines in the end and side walls diverging from the respective vertical lines to the free edges of said end and side walls in the provision of opposed flap forming members each including an outer layer and opposed inner layers joined therewith on corresponding ones of said fold lines and having adjacent spaced edges, applying adhesive to relatively narrow zones of said cuff adjacent the free end thereof, each of said zones extending entirely across a folded end wall and the respective flap forming inner layers, applying adhesive to the inner surface of the outer layer of one of ,said flap forming members in a relatively narrow zone adjacent its free edge, and with said zone terminating in fold lines between said outer and inner.layers, folding the other flap forming member .overthefoldedend walls whereby the adhesive on theinner layers of said memberand that on .theend wallsare brought into contact, and thereafter foldingsaid one of the flap-forming membersover said other flap-forming member wherebythe adhesive on said one flap forming member contacts the outer surface of its opposed inner layer and the outer surface of the other flap-forming member whereby all passages formed .by the folds of theclosing flaps and communicating with the interior of the bag'are sealed.

2. The method defined in claim 1 in which all of said adhesive areas-are substantially parallel to the free edge of said cuff, the upper limits thereof being spaced from said free edge and the lower limits thereof beingspaced from the level of fill.

3. The method defined in claim 1 in which the upper limits of the adhesive area on said one of said flap-forming members is spaced from the free edge thereof and the lower limits thereof overlap the free end of the other of said flap-forming members when said closure is completed, so as to be spaced from the contents.

4. The method of making a sift-proof top closure from the cuff of a tubular bag projecting above the surface of the fill thereof and wherein said cuff includes end and side walls intersecting in vertical lines; said method comprising the following successive steps, folding the end walls inwardly over the fill about horizontal lines adjacent said surface and simultaneously therewith providing fold lines in the end and side walls which provide opposed flap forming members each including an outer layer and opposed inner layers joined therewith on corresponding ones of said fold lines and having adjacent spaced edges, applying adhesiveto relatively narrow zones of said cuif adjacent the *free'end thereof, each of said zones extending entirely across a folded end-wall and therespective flap forming inner layers, applying adhesive to'the inner surface of the outer layer of one'of said flap forming members in a relatively narrow zone adjacent its free edge, and

with said zone terminatingin'fold lines between said outer and inner layers, folding the-other fiap forming member over the folded end walls whereby the adhesive on the inner layers of said memher and that ontheend walls'are brought into contact, and thereafter folding said one of the fiapforming members over said other flap-forming member whereby the adhesive on said one flap forming member contacts theouter surface of its opposedinner layerandthe outer surface of the other flap-forming member whereby all passages formed by the folds of the closing fiapsand communicating with the interior of the bag are sealed.

References-Citedin the fileof this patent UNITED "STATES PATENTS Number Name Date 363,596 Claussen -May 24, 1887 411,288 Lorenz Sept. 17, 1889 665,287 Tyson Jan. 1, 1901 1,026,356 Lee May 14, 1912 1,425,481 Howard Aug. 8, 1922 -1;491,269 Joplin Apr. 22, 1924 1,989,471 Belcher Jan. 29, 1935 2,289,228 Kindseth Apr. '14, 1942 FOREIGN PATENTS Number Country Date 519,147 GreatBritain, Mar. 18, 1940 

